Correcting low-end peaks/troughs

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kevinkace
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Location: Seattle, WA
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Correcting low-end peaks/troughs

Post by kevinkace »

First post - I read through the posting guide, so hopefully I have everything covered!

Overview: I've been recording/producing for 20ish years. Currently non-professionally in my home studio, and I want to fix the low-end peaks/troughs in my monitoring.

My room is fairly well insulated, neighbours are far away, loudness is never an issue.
I'm currently using an old Blue Sky System One - 2x 6.5" satellites, and a KRK Rokit 10s (the original System One sub died on me a few years ago).
I'll probably upgrade, and get rid of the sub (as I assume 2 speakers are easier to tune than 2.1).

The north and east walls are 6" thick, with offset studs, filled with Roxul, 2x1/2" drywall on the outside, 1x5/8" on the inside.
The south and west walls are also drywall, 5/8", studded out 1-1/2" over concrete foundation. Minimal insulation.
The ceiling is 1/2" drywall, 8" joists, around 16" oc, running east-west. 7'-4" high. Some Roxul toward the east side
The floor is 3/16" padded vinyl laminate, over concrete.

I ran REW, with and without the sub. There isn't much difference, other than the amplitude of the peaks/troughs.
Here's a sweep from 10-500hz, 1/12 oct smoothing.

1. brown - right with sub
2. aqua - left with sub
3. orange - right, no sub
4. blue - left, no sub
zoom- 10-500.png
If I'm reading this right:
- peaks/troughs 25-70hz
- left peak/trough 110-130hz
- trough 210hz
- right peak 230hz

Here's a 20-20k sweep, 1/12 oct smoothing:

1. brown - right with sub
2. blue - left with sub
zoom- 20-20000.png
On to the room. It's a strange shape, and I'm happy to rearrange.
plot.png
west.png
north.png
east.png
south - Copy.png
Hopefully they are adequately labeled, but in general:
- 7'-4" ceiling
- 11'-8" x 13'-8", with 2 corners protruding in
- a 6" x 8" beam across the short width
- 32" x 6'-7" door, flush with interior wall
- 2'-11" x 2'-5" window, inset 9"

Budget (USD):
Monitors: $2000-$3000
Construction: $2000 materials (I can do the work myself)

As for resolving these issues, I'm happy to build bass traps or whatever is needed, but I want to be sure I'm making things better, not worse!
How to approach?
- change room orientation
- add bass traps, super chunks, re-measure, rinse/repeat
- 3D model room, to find optimal solution
- new monitors, without sub (right now I'm mostly doing electronic music, so accurate/full low-end is important)

Thanks!

(Edit - looking at monitors, and upped my budget...)
DanDan
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Re: Correcting low-end peaks/troughs

Post by DanDan »

Waterfall graphs show how the FR changes over time, with some frequencies really hanging about.
REW can answer all questions better than any guesses. Post your. mdat and people will probably show you how to look into the tea leaves....
But there are generic treatment recommendations. Realtraps.com and GIKacoustics.com have extensive how what where and why. My take:- Cloud as big as you can manage, or entire absorbent suspended ceiling. Trap the corners with deep devices, you could easily DIY something like SoffiTraps. Wall Ceiling junctions are just as much Corner as any others.
Side reflections need to be absorbed, again as deep as possible traps. Back wall causes havoc, it is worth thinking about trapping the whole thing.
Drums will ring and appear in your graphs unless you completely damp them.
kevinkace
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Location: Seattle, WA
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Re: Correcting low-end peaks/troughs

Post by kevinkace »

Thanks DanDan.

While doing more research I came across tuned membrane dampeners, which look an awful lot like a drum... I'm looking into dampening them now.

Here's the 10-500hz mdat:
RM - 12oct 10-500.mdat
Here's a 20-20k mdat (too bit to upload): https://drive.google.com/file/d/1YtjjDC ... sp=sharing
DanDan
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Re: Correcting low-end peaks/troughs

Post by DanDan »

Tx Kevin. In terms of identifying the measurements, what do these letters mean? l, nf, ns, op
BTW I wouldn't bother with Loopback or Soundcard Calibration.
kevinkace
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Location: Seattle, WA
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Re: Correcting low-end peaks/troughs

Post by kevinkace »

l - left
r - right
nf - no filter on satellite speakers
ns - no sub
op - optimal listening position

On that last note, I need to adjust my computer screens and monitor position as my optimal listening position is father back than where I'd comfortably use my keyboard/mouse.
I've seen both arguments: monitors as close to the wall as possible, or further away. I guess I should try a few speaker/chair arrangements and measure.
DanDan
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Re: Correcting low-end peaks/troughs

Post by DanDan »

Tx. Genelec used to recommend closer than 0.2M or farther then 2.2M
Of course if the LCR speakers are crossed over, different ball game.
The Optimum position will change with different speaker locations. These things interact.
Often I use the RTA zoomed to LF. Pink Noise PN. Move a speaker or listening position, instant result. It is at least very useful for quickly identifying no fly zones.
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